Beam-rotation digital holographic microtomography utilizes the rotating mirror for changing incident angle of the incident beam onto a sample, and calculates the three-dimensional (3D) spectrum distribution of the measured sample by recording optical field of the incident beam at different angles, so as to achieve the three-dimensional refractive index distribution inside the sample. The method is applied to the observation of the images of living cells to reach the sub-micron lateral resolution. However, this method has poor longitudinal resolution, which will result in the difficulty of observing the complete 3D tomographic images.
Furthermore, measuring technology of the traditional holographic tomography further comprises:
(a) Sample-rotation digital holographic tomography: this technique is similar to the known computer tomography, which records transmitting optical field at different angle by surrounding the sample, and the general implementation is directly rotating the object to be tested or its carrier; can be applied for optical fiber detection, directly rotating optical fiber during digital holographic recording to reach the purpose of tomography information access; in addition can also be used for the detection of biomedical cell. The drawbacks include complex sample preparation and harsh shooting conditions, which results in disadvantage of biomedical system promotion. In addition, there are still some problems in the mechanical stability for the sample rotation mode improvement. A holographic optical tweezer is manipulated to directly rotating the sample, which three-dimensional resolution is affected by the restricted rotation angle.
(b) Optical coherence tomography: this technique is commonly used in the detection of biomedical living cells and tissues. It can be used to detect the samples of living organisms by optical slicing, based-on low coherence light source with short coherence window. It can be applied in clinic. The disadvantage is that it is difficult to apply to the detection of living cells due to the poor horizontal and vertical resolution.
(c) Fluorescence laser confocal microscope: this technology is commonly used in the detection of biomedical cells, through point-to-point, layer-by-layer scanning mechanism of confocal microscope, fluorescence dyeing and stimulated image information inside the sample are obtained. The disadvantage is that it has a low vertical resolution, and the dyeing has damaged the cells.
In recent years, Taiwan is actively developing life medicine and other related industries, and the output value is increased by 17% in the last year (2016). The government will invest billions of dollars to enter the relevant industries in order to reach the trillion output value in the future. The invention provides a tomographic imaging tool, which is expected to be used for the analysis of the structure of living cells and the diagnosis of biochemical characteristics. In addition, in the industrial inspection and fiber communication industry, the present invention can also be used in the detection of micro optical elements and particle structures, or for the detection of the internal structure and refractive index of optical fiber and the analysis of the optical waveguide characteristics. Due to long-term lack of innovation time-space detection mechanism in industrial inspection, the invention reveals its importance in the future development, and the terminal products can be expanded to the United States, being positive development of Photoelectric Industrial Technology. Therefore, it is very useful in industry, and has potential marketing.
However, at present, there is some drawbacks in holographic tomography technology for industrial applications. It is necessary to develop a novel tomography technology to solve the above problems.